First feeding of marine ornamental goby Amblygobius phalaena: investigating the optimal initial live feed organisms and its feeding density

The white-barred goby, Amblygobius phalaena, is a popular ornamental fish in the marine aquarium market. To achieve successful commercial production, efficient larval rearing techniques are crucial. Previous studies have achieved successful cultivation of A. phalaena larvae using a combination of three live feed organisms: ciliates Euplotes sp., rotifers Brachionus rotundiformis, and copepod Apocyclops royi nauplii during the first feeding stage. However, the specific contributions of these live feed organisms to larval survival and growth remain unclear. Moreover, the optimal feeding density for the critical initial live feed organism has not been determined experimentally. In this study, we aimed to enhance the larviculture protocol for A. phalaena by introducing oyster trochophores and addressing these knowledge gaps. Our experiments revealed that A. phalaena larvae could consume both oyster trochophores and Euplotes sp. during the first feeding stage. However, larva exhibited superior survival and growth performance when fed oyster trochophores. The optimal feeding density of oyster trochophores was determined to be 10 individuals (ind.)/mL, while a feeding density as high as 20 ind./mL resulted in decreased larval feeding incidence. These findings have significant implications for enhancing larval production programs of marine ornamental gobies and promoting their sustainable commercialization.